Milling cutter and milling insert with coolant delivery

ABSTRACT

A cutting insert for use in chipforming and material removal from a workpiece wherein coolant is supplied to the cutting insert from a coolant source. The cutting insert includes at least one discrete cutting location and at least one distinct internal channel that corresponds to the cutting location. The internal channel has an inlet to receive coolant and an outlet to exit coolant. The outlet is proximate to the cutting location, and the inlet is radial inward of the outlet.

BACKGROUND OF THE INVENTION

The invention relates to a milling cutter, as well as a milling insert,used for chipforming and material removal operations. More specifically,the invention pertains to a milling cutter, as well as a milling insert,used for chipforming and material removal operations wherein there isenhanced delivery of coolant adjacent the interface between the millinginsert and the workpiece (i.e., the insert-chip interface) to diminishexcessive heat at the insert-chip interface.

In a chipforming and material removal operation (e.g., a millingoperation), heat is generated at the interface between the cuttinginsert and the location where the chip is removed from the workpiece(i.e., the insert-chip interface). It is well-known that excessive heatat the insert-chip interface can negatively impact upon (i.e., reduce orshorten) the useful tool life of the milling insert. As can beappreciated, a shorter useful tool life increases operating costs anddecreases overall production efficiency. Hence, there are readilyapparent advantages connected with decreasing the heat at theinsert-chip interface.

In this regard, U.S. Pat. No. 6,053,669 to Lagerberg discusses theimportance of reducing the heat at the insert-chip interface. Morespecifically, Lagerberg mentions that when the cutting insert is madefrom cemented carbide reaches a certain temperature, its resistance toplastic deformation decreases. A decrease in plastic deformationresistance increases the risk for breakage of the cutting insert. U.S.Pat. No. 5,775,854 to Wertheim points out that a rise in the workingtemperature leads to a decrease in hardness of the cutting insert with aconsequent increase in wear of the cutting insert. Each one of theLagerbeg patent and the Wertheim patent discuss the importance ofdelivering coolant to the insert-chip interface.

Other patent documents disclose various ways to or systems fordelivering coolant to the insert-chip interface. In this regard, U.S.Pat. No. 6,045,300 to Antoun discloses using high pressure and highvolume delivery of coolant to address heat at the insert-chip interface.U.S. Patent Application Publication No. 2003/00820118 to Kreamerdiscloses grooves between the cutting insert and a top plate. Coolantsflows through the grooves to address the heat at the insert-chipinterface. U.S. Pat. No. 5,901,623 to Hong discloses a coolant deliverysystem for applying liquid nitrogen to the insert-chip interface.

It is readily apparent that in a chipforming and material removaloperation, higher operating temperatures at the insert-chip interfacecan have a detrimental impact on the useful tool life through prematurebreakage and/or excessive wear. It therefore would be highly desirableto provide a cutter assembly (e.g., a milling cutter assembly), as wellas a cutting insert (e.g., a milling insert), used for chipforming andmaterial removal operations wherein there is an improved delivery ofcoolant to the interface between the milling insert and the workpiece(i.e., the insert-chip interface, which is the location on the workpiecewhere the chip is generated).

In a milling operation, the chip generated from the workpiece cansometimes stick (e.g., through welding) to the surface of the cuttinginsert (e.g., a milling insert). The build up of chip material on thecutting insert in this fashion is an undesirable occurrence that cannegatively impact upon the performance of the cutting insert, and hence,the overall material removal operation.

Thus, it would be highly desirable to provide a cutting assembly (e.g.,a milling cutter assembly), as well as a cutting inert (e.g., a millinginsert), used for chipforming and material removal operations whereinthere is enhanced delivery of coolant to the insert-chip interface so asto result in enhanced lubrication at the insert-chip interface. Theconsequence of enhanced lubrication at the insert-chip interface is adecrease in the tendency of the chip to stick to the cutting insert.

In a cutting operation such as, for example, a milling operation, therecan occur instances in which the chips do not exit the region of theinsert-chip interface when the chip sticks to the cutting insert. When achip does not exit the region of the insert-chip interface, there is thepotential that a chip can be re-cut. It is undesirable for the millinginsert to re-cut a chip already removed from the workpiece. A flow ofcoolant to the insert-chip interface will facilitate the evacuation ofchips from the insert-chip interface thereby minimizing the potentialthat a chip will be re-cut.

Hence, it would be highly desirable to provide a cutting assembly (e.g.,a milling cutter assembly), as well as a cutting inert (e.g., a millinginsert), used for chipforming and material removal operations whereinthere is enhanced delivery of coolant to the insert-chip interface so asto reduce the potential that a chip will be re-cut. The consequence ofenhanced flow of coolant to the insert-chip interface is betterevacuation of chips from the vicinity of the interface with a consequentreduction in the potential to re-cut a chip.

SUMMARY OF THE INVENTION

In one form thereof, the invention is a cutting insert for use inchipforming and material removal from a workpiece wherein coolant issupplied to the cutting insert from a coolant source. The cutting insertincludes at least one discrete cutting location and at least onedistinct internal channel that corresponds to the cutting location. Theinternal channel has an inlet to receive coolant and an outlet to exitcoolant. The outlet is proximate to the cutting location, and the inletis radial inward of the outlet.

In another form thereof, the invention is a cutting insert for use inchipforming and material removal from a workpiece wherein coolant issupplied to the cutting insert from a coolant source. The cutting insertincludes a cutting insert body that presents a plurality of discretecutting locations. The cutting insert body contains a plurality ofdiscrete depressions corresponding to one of the cutting locations andextending toward its corresponding one of the cutting locations. Thereis a diverter plate that has a central body with a top face and a bottomface, and a plurality of tapered flanges. The diverter plate is affixedto the cutting insert body wherein each one of the tapered flanges isreceived within a corresponding one of the discrete depressions so thateach one of the discrete depressions and its corresponding one of thetapered flanges and a portion of the central body define one of aplurality of discrete internal channels. Each one of the discreteinternal channels corresponds to one of the cutting locations. Each oneof the internal channels has an outlet to exit coolant being proximateto the corresponding cutting location and an inlet to receive coolantbeing radial inward of the outlet.

In yet another form thereof, the invention is a cutting insert for usein chipforming and material removal from a workpiece wherein coolant issupplied to the cutting insert from a coolant source. The cutting insertincludes a cutting insert body that presents at least one discretecutting location. The cutting insert body contains at least one discretedepression that corresponds to the cutting location and extends towardthe corresponding cutting location. There is a diverter plate that has acentral body with a top face and a bottom face, and at least one taperedflange. The diverter plate is affixed to the cutting insert body whereinthe tapered flange is received within the discrete depression so thatthe discrete depression and the corresponding tapered flange and aportion of the central body define at least one discrete internalchannel that corresponds to the cutting location. The internal channelhas an outlet to exit coolant that is proximate to the correspondingcutting location and an inlet to receive coolant being radial inward ofthe outlet.

In still another form thereof, the invention is a cutting insert for usein chipforming and material removal from a workpiece wherein coolant issupplied to the cutting insert from a coolant source. The cutting insertincludes a mediate cutting insert body that defines a peripheral flanksurface and a peripheral portion of opposite rake surfaces wherein theperipheral flank surface intersects the peripheral portion of theopposite rake surfaces to form discrete cutting locations. There is apair of rake plates attached to the mediate cutting insert body whereineach one of the rake plates defines in part its corresponding one of therake surfaces. The mediate cutting insert body and the rake platestogether define a first group of a plurality of discrete internalchannels and a second group of a plurality of discrete internalchannels. Each one of the first group of discrete internal channelscorresponds to one of the cutting locations at the intersection of oneof the rake surfaces and the peripheral flank surface. Each one of thesecond group of discrete internal channels corresponds to one of thecutting locations at the intersection of other of the rake surfaces andthe peripheral flank surface. Each one of the first group of thediscrete internal channels has an inlet opening at the other of the rakesurface and an outlet opening at the one rake surface adjacent to itscorresponding cutting location. Each one of the second group of thediscrete internal channels has an inlet opening at the one of the rakesurface and an outlet opening at the other rake surface adjacent to itscorresponding cutting location.

In still another form thereof, a milling cutter for use in chipformingand material removal from a workpiece wherein coolant is supplied to themilling cutter from a coolant source. The milling cutter includes amilling cutter body that contains a coolant reservoir and a pocket thathas a pocket opening in communication with the coolant source. Themilling cutter body contains a fluid passageway that provides fluidcommunication between the coolant reservoir and the pocket. There is acutting insert that includes at least one discrete cutting location andat least one distinct internal channel that corresponds to the cuttinglocation. The internal channel has an inlet to receive coolant and anoutlet to exit coolant wherein the outlet is proximate to the cuttinglocation and the inlet is radial inward of the outlet.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a brief description of the drawings that form a part ofthis patent application:

FIG. 1 is an isometric view of a specific embodiment of the millingcutter assembly of the invention wherein the milling cutter bodypresents pockets spaced about the circumference thereof, and whereinsome of the pockets are shown being empty (i.e., without a millinginsert assembly therein), and two of the pockets are show as containinga milling insert assembly with the flow of coolant shown by arrows;

FIG. 2 is an isometric side view of one pocket contained in the cuttingrim of the milling cutter body showing the leading concave surface andthe seating section, and wherein the pocket is illustrated in theenvironment of the milling cutter body shown in phantom;

FIG. 3 is an isometric view of the milling cutter assembly of FIG. 1showing the milling cutter body with the reservoir cap and the retentionknob exploded away from the milling insert body to expose the centralcoolant reservoir, and wherein the flow of coolant is illustrated byarrows;

FIG. 4 is a side view of the lock screw of FIG. 3 with a portion thereofcut away to show the central bore and auxiliary inclined bores thereof,and wherein the flow of coolant is shown by arrows;

FIG. 5 is a top view of the reservoir cap of FIG. 3;

FIG. 6 is a cross-sectional view of the reservoir cap taken alongsection line 5-5 of FIG. 5;

FIG. 7 is an isometric view of the milling insert with the plateexploded away from the milling insert body;

FIG. 8 is a plan view showing the rake surface of the milling insertbody that contains the discrete depressions therein;

FIG. 9 is a cross-sectional view of the milling insert body of FIG. 8taken along section line 9-9;

FIG. 10 is a plan view showing the top surface of the plate;

FIG. 11 is a cross-sectional view of the plate of FIG. 10 taken alongsection line 11-11;

FIG. 12 is an isometric view of the plate showing the bottom surface ofthe plate;

FIG. 13 is an isometric view of the milling insert assembly of FIG. 1showing the bottom surface of the milling insert;

FIG. 14 is a cross-sectional view of the milling insert of FIG. 14 takenalong section line 14-14 of FIG. 14;

FIG. 15 is an isometric view of the specific embodiment of the millinginsert assembly of FIG. 1 wherein the clamp, the milling insert body,the plate and the shim are exploded apart from one another;

FIG. 16 is an isometric view of a second specific embodiment of themilling insert assembly wherein the top rake plate and bottom rake plateare exploded apart from the milling insert body;

FIG. 16A is an isometric view of the top rake plate of FIG. 16;

FIG. 17 is a cross-sectional view of the milling insert assembly of FIG.14, when in an assembled condition;

FIG. 18 is an isometric view of a specific embodiment of a shim used inconjunction with the milling insert of FIG. 7;

FIG. 19 is an isometric view of another specific embodiment of a millinginsert wherein the rake plate is exploded away from the milling insertbody;

FIG. 20 is an isometric view of the specific embodiment of FIG. 19showing the bottom surface and the peripheral flank surface of themilling insert;

FIG. 21 is a cross-sectional view of the milling insert of FIG. 19 withthe rake plate assembled to the milling insert body;

FIG. 22 is a cross-sectional view of the milling insert of FIG. 19 withthe rake plate assembled to the milling insert body;

FIG. 23 is an isometric view of another specific embodiment of a millingcutter assembly showing the milling insert of FIGS. 19-22 exploded awayfrom the pocket of the milling cutter body;

FIG. 24 is an isometric view of the specific embodiment of the millingcutter assembly of FIG. 23 wherein the milling cutter body is rotated sothat the bottom surface of he milling inert is visible;

FIG. 25 is an isometric view of a portion of the milling cutter body ofstill another specific embodiment of a milling cutter assembly wherein ashim is not necessary, and the milling insert has been removed from thepocket; and

FIG. 26 is another isometric view of the pocket of the milling cutterbody of FIG. 25.

DETAILED DESCRIPTION

Referring to the drawings, FIG. 1 illustrates a specific embodiment ofthe milling cutter assembly of the invention generally designated as 40wherein the milling cutter assembly 40 is for use in chipforming andmaterial removal operations. In such an operation, the material isremoved from a workpiece. In operation, the milling cutter assembly 40rotates in the direction indicated by the arrow “R”.

Milling cutter assembly 40 includes a generally cylindrical millingcutter body generally designated as 42 that has a cutting rim 44 with aperipheral surface 46. Milling cutter 40 further includes a dependingintegral collar 48 that depends downward (as viewed in FIG. 1) from thecutting rim 44. In this specific embodiment, milling cutter assembly 40further contains a plurality of spaced-apart pockets generallydesignated as 52 in the peripheral surface 46 of the cutting rim 44. Aswill be described in more detail hereinafter, each pocket 52 receivesand securely retains a milling insert assembly therein.

It should be appreciated that the milling cutter body 42 may contain anumber of pockets different from that shown in this specific embodiment.Further, it should also be appreciated that the spacing between thepockets may be different from that disclosed herein. In this regard, thenumber and position of the pockets can vary depending upon the specificapplication for the milling cutter assembly. Applicants do not intend tolimit the scope of the invention to the specific geometry of the millingcutter body and orientation of the pockets therein such as those shownin the drawings herein.

Each pocket 52 has a leading concave surface 54 and a seating section(see bracket 60 in FIGS. 1 and 2) that is contiguous with and trails theleading concave surface 54. A transition region 58 provides a transitionbetween the concave surface 54 and the seating section 60. In thecontext of this invention, the terms “leading” and “trailing” (as wellas like related terms) refer to the relative position of the structuralaspects of the pocket and the milling insert assembly in reference tothe operation of the milling cutter assembly. For example, in referenceto the same component, a portion there of that is “leading” isrotationally ahead of a portion thereof that is “trailing” during theoperation of the milling cutter assembly. The use of these relativeterms is not intended to be restrictive of the scope of the invention,but only to define the various features of the structure relative to oneanother.

The seating section 60 includes a seating surface 62 at the trailing endof the seating section 60. Seating surface 62 has a radial dispositionand an axial disposition. Seating surface 62 has a top edge 64 and abottom edge 66. The milling cutter body 42 contains a closed threadedbore 68 that has a termination in the seating surface 62. The threadedbore 68 receives a threaded fastener as described hereinafter. The useof the terms “top” and “bottom” and the like are in reference to therelative orientation of the structural components as shown in theposition as illustrated in FIG. 1. The use of these relative terms isnot intended to be restrictive of the scope of the invention, but onlyto define the various features of the structure relative to one another.

Seating section 60 further contains a trailing inclined seating surface74 that joins the seating surface 62. The milling cutter body 42contains a coolant passage 76 that opens at the trailing inclinedseating surface 74 as shown by an opening 77. The opening 77 is offsetfrom the geometric center of the seating surface 62 so as to register(or be in alignment) with a selected lobe of the central coolant passageof the milling insert depending upon the position of the milling insertin the pocket. This aspect of the invention will be describe din moredetail hereinafter.

The coolant passage 76 provides a conduit for the flow of coolant to themilling insert contained in the pocket as will be described hereinafter.The seating section 60 also contains a leading inclined seating surface80 that is contiguous with the trailing inclined seating surface 74.When the milling insert assembly is retained within the pocket, themilling insert rests on (and is supported by) the leading inclinedseating surface 80 and the shim rests on and is supported by thetrailing inclined seating surface 74. It should be appreciated that theleading inclined seating surface 80 and the trailing inclined seatingsurface 74 have a radial disposition and an axial disposition.

The seating section 60 further includes a clamp seating surface 84 thatis adjacent to the leading inclined seating surface 80. A shoulder 86joins the leading inclined seating surface 80 with the clamp seatingsurface 84. Another shoulder 88 provides a transition between the clampseating surface 84 and the transition 58. The clamp seating surface 84,as well as the shoulders 86 and 88, have a radial and an axialdisposition. The milling cutter body 42 contains a threaded hole (oraperture) 90 that opens at the clamp seating surface 84. Threaded hole90 is designed to receive a retention pin that passes through a clampwherein the clamp assists to securely retain the shim and milling insertin the pocket.

As illustrated in FIG. 3, the milling cutter body 42 further includes acentral coolant (or fluid) reservoir 94 that is in communication with acoolant source designated in FIG. 3 as COOLANT SOURCE. The centralcoolant reservoir 94 is defined (at least in part) by a centralupstanding wall 96 which has an upward (or has a generally verticalorientation as viewed in FIG. 3). The upstanding wall 96 extendsupwardly from the bottom surface 98 of the milling cutter body 42wherein the bottom surface 98 also defines (in part) the central coolantreservoir 94. The central upstanding wall 96 has a top edge 100 asviewed in FIG. 3.

The central upstanding wall 96 contains a coolant passage 76 thatprovide fluid communication between the coolant reservoir 94 and thepocket 52. Each coolant passage 76 corresponds to a pocket 52 in thatcoolant is supplied to the corresponding pocket 52 through thecorresponding coolant passage 76. Although applicants do not intend tobe restricted to coolant passages 76 of any specific size or internalgeometry, applicants contemplate that the dimension and geometry of eachcoolant passage 76 are such to provide for adequate flow of coolant tothe corresponding pocket, and hence, to the corresponding milling insertretained in the pocket. Further, applicants contemplate that as opposedto being a single coolant passage, there may be a plurality (e.g., apair) of coolant passages that supply coolant to each pocket from thecentral coolant reservoir.

As shown in FIGS. 3 and 4, the milling cutter assembly 40 furthercontains a lock screw generally designated as 106. Lock screw 106 has atop end 108 and a bottom end 110 as viewed in FIG. 4. Lock screw 106 hasan enlarged diameter section 112, which defines a shoulder 114, adjacentto the top end 108 thereof. An elongate integral cylindrical shank 116projects from the enlarged diameter section 112. The lock screw 106contains a central longitudinal hexagonal bore 118 therein that travelsthrough the length thereof.

The lock screw 106 further contains a plurality of radial inclined bores124 disposed at an angle to the longitudinal axis Z-Z of the lock screw106. Each one of the inclined bores 124 provides fluid communicationbetween central bore 118 and the top circular corner 122 of the lockscrew 106. These inclined bores 124 provide additional passages throughwhich coolant can travel from the coolant source to the coolantreservoir. As shown in FIGS. 3 and 4 by the arrows, coolant enters thehexagonal bore 118 at the bottom end 120 thereof and flows through bore118 so that the coolant exits the hexagonal bore 118 at the top end 122thereof. The coolant also exits the central bore 118 via the inclinedbores 124 as shown by the arrows. The coolant that exits the lock screw106 (whether via the central bore 118 or the inclined bores 124) thenflows to enter the central coolant reservoir 94 as illustrated by thearrows.

As illustrated in FIGS. 5 and 6, the milling cutter assembly 40 alsoincludes a reservoir cap generally designated as 126, which defines inpart the central coolant reservoir 94. Reservoir cap 126 has a topsurface 128 and a bottom surface 130. The reservoir cap 126 contains aplurality of bolt holes 132, which are located in an equi-spaced fashionat the periphery of the reservoir cap 126. Each one of the bolt holes132 is adapted to receive a bolt 134 (see FIG. 3) to affix the reservoircap 126 to the milling cutter body 42. The reservoir cap 126 furtherincludes a depending generally circular integral flange 136 thatcontains a plurality of notches 138 wherein the notches 138 areequi-spaced about the circumference of the flange 136.

Referring to FIG. 1, the milling cutter assembly 40 further includes aplurality of milling insert (or cutting insert) assemblies wherein eachone of the milling inserts is generally designated as 150. As isapparent from FIG. 1, each one of the pockets 52, and in particular theseating sections 60, receive and retain a milling insert assembly 150.The milling insert assembly 150 contains a number of components; namely,the milling insert (which can be more broadly considered as a cuttinginsert), the shim, the clamp and threaded members, which are describedin more detail hereinafter. It should be appreciated that applicantscontemplate that the term “cutting insert” is inclusive (withoutlimitation) of milling inserts and turning inserts, as well as otherstyles and kinds of inserts used to engage the workpiece and removematerial in a material removal operation such as, for example, achipforming and material removal operation.

As mentioned above, the milling insert assembly 150 includes a shimgenerally designated as 152. One specific embodiment of the shim 152 isillustrated in FIG. 15. Shim 152 presents a top surface 154, a bottomsurface 156 and a peripheral flank (or edge) surface 158. Shim 152contains a pair of bores therein. One of these bores is a fastener bore160 that receives a threaded member 164 that affixes the shim 152 andthe milling insert to the milling cutter body 42 in a fashion known tothose of ordinary skill in the relevant art. Shim 152 also presents fourcorners (162A, 162B, 162C, 162D) wherein corners 162B and 162C are sharpcorners and corners 162A and 162D are flat corners defined by a flatsurface.

The other bore 166 is a coolant bore in alignment with the pocketopening 77 when the milling insert assembly 150 is affixed in the pocket52. As one can appreciate from FIG. 18, the coolant bore 166 is offsetfrom the geometric center of the top surface 154 of the shim 152. Thenature of the offset of coolant bore 166 is like that for opening 77 sothat the coolant bore can register or align with a selected lobe of thecentral coolant passage of the milling insert depending upon theposition of the milling insert in the pocket. As shown by the arrows inFIGS. 15 and 18, coolant flows from the coolant bore 166 bore 168 intothe milling insert as will be described hereinafter.

Referring to FIGS. 7 through 15, the milling insert assembly 150includes a milling insert generally designated as 170. Milling insert170 has a milling insert body 172 and a corresponding plate 174 whereinthe plate 174 attaches to the milling insert body 172 to form themilling insert 170.

The diverter plate 174 can be attached or affixed to the milling insertbody 172 in any one of a number of different ways. In this regard, thesecomponents (i.e., the milling insert body and the diverter plate) can beaffixed together by adhesive or braze or the like. The milling insertbody and the diverter plate may be sintered together to form a singlemilling insert. As still another alternative, the structure defined bythe combination of the milling insert body and diverter plate can beformed as a monolithic body via a powder metallurgical technique that issuitable to make a body with an internal channel. In this regard, thefollowing patent documents are exemplary of powder metallurgical methodsto make a body with internal passages: U.S. Pat. No. 4,881,431 toBieneck for a Method of Making a Sintered Body having an InternalChannel, and U.S. Pat. No. 6,860,172 to Hecht for a Method for Making aPowdered Metal Compact.

The milling insert (including the milling insert body and the diverterplate) may be made from one of any number of materials that are suitablefor use as a cutting insert. The following materials are exemplarymaterials useful for a cutting insert: tool steels, cemented carbides,cermets or ceramics. The specific materials and combinations ofmaterials depend upon the specific application for the milling insert.Applicants contemplate that the milling insert body and the diverterplate may be made from different materials.

In reference to tool steels, the following patent documents disclosetool steels suitable for use as a cutting insert: U.S. Pat. No.4,276,085 for High speed Steel, U.S. Pat. No. 4,880,461 for Superhardhigh-speed tool steel, and U.S. Pat. No. 5,252,119 for High Speed ToolSteel Produced by Sintered Powder and Method of Producing the Same. Inreference to cemented carbides, the following patent documents disclosecemented carbides suitable for use as a cutting insert: U.S. PatentApplication Publication No. US2006/0171837 A1 for a Cemented CarbideBody Containing Zirconium and Niobium and Method of Making the Same,U.S. Reissue Patent No. 34,180 for Preferentially Binder EnrichedCemented Carbide Bodies and Method of Manufacture, and U.S. Pat. No.5,955,186 for a Coated Cutting Insert with A C Porosity Substrate HavingNon-Stratified Surface Binder Enrichment. In reference to cermets, thefollowing patent documents disclose cermets suitable for use as acutting insert: U.S. Pat. No. 6,124,040 for Composite and Process forthe Production Thereof, and U.S. Pat. No. 6,010,283 for a Cutting Insertof a Cermet Having a Co—Ni—Fe Binder. In reference to ceramics, thefollowing patent documents disclose ceramics suitable for use as acutting insert: U.S. Pat. No. 5,024,976 for an Alumina-zirconia-siliconcarbide-magnesia Ceramic Cutting Tools, U.S. Pat. No. 4,880,755 for aSialon Cutting Tool Composition, U.S. Pat. No. 5,525,134 for a siliconNitride Ceramic and Cutting Tool made Thereof, U.S. Pat. No. 6,905,992for a Ceramic Body Reinforced with Coarse Silicon Carbide Whiskers andMethod for Making the Same, and U.S. Pat. No. 7,094,717 for a SiAlONContaining Ytterbium and Method of Making.

Milling insert body 172 has a peripheral rake surface 178 that extendsabout the periphery of the milling insert body 172, an opposite bottomsurface 180, and a peripheral flank surface 182. The peripheral rakesurface 178 surrounds a plurality of discrete (generally concave)depressions (186, 188, 190, 192) contained in the milling insert body172. Because each one of the discrete depressions is essentially alike,a description of discrete depression 186 will suffice for thedescription of the other discrete depressions (188, 190, 192). In thisregard, discrete depression 186 has a radial inward boundary 196 and aradial outward boundary 198.

Milling insert body 172 further contains a central coolant passageway200 in the bottom surface 180 thereof. Coolant passageway 200 has fourequi-spaced apart radial lobes (202, 204, 206, 208) wherein each lobeextends in a radial outward direction toward its corresponding cuttingedge (or cutting location) as described hereinafter. Milling insert body172 still further contains a central generally concave indention 212that surrounds the central coolant passageway 200. Central indention 212defines four sealing surfaces (214, 216, 218, 220), which have anarcuate (or concave) surface, between adjacent discrete depressions.These sealing surfaces extend from the central coolant passage 200 tothe peripheral rake surface 178. More specifically, sealing surface 214is between discrete depression 186 and discrete depression 188, sealingsurface 216 is between discrete depression 188 and discrete depression190, sealing surface 218 is between discrete depression 190 and discretedepression 192, and sealing surface 220 is between discrete depression192 and discrete depression 186.

The sealing surfaces (214, 216, 218, 220) are locations where themilling insert body and the diverter plate join. As will be describedhereinafter, in the case of a two-piece (i.e., the milling insert bodyand the diverter plate) milling insert, these seals in the vicinity ofthe sealing surfaces may be formed via secure surface-to-surface contactin the case of a strong force (e.g., a clamping force) exerted againstthe milling insert to urge the diverter plate against the milling insertbody. In the case where a single piece milling insert is formed byjoining together the milling insert body and the diverter plate, theseal in the vicinity of the sealing surfaces could be formed due to thejoinder, such as, for example, by sintering or brazing, of thecomponents together along the adjacent surface areas. The same is truein the case of where the components are joined along adjacent surfaceareas by adhesive or the like. In the case where the milling insert is amonolithic body, the discrete internal channels (which could have ageometry like that of the interior channels formed via the assembly ofthe milling insert body and the diverter plate) would be formed by asinternal channels in the interior of the part during formation whereinthe volume of material in the vicinity of the sealing surfaces wouldfunction as barriers to define the discrete internal channels.

A specific lobe of the central coolant passageway 200 intersects eachone of the discrete depressions. In this regard, lobe 202 intersectsdiscrete depression 186, lobe 204 intersects discrete depression 188,lobe 206 intersects discrete depression 190, and lobe 208 intersectsdiscrete depression 192. In reference to discrete depression 186, whichhas application to the other discrete depressions, there is a boundary224 at the intersection between the discrete depression 186 and the lobe202 of the central coolant passageway 200.

Milling insert body 172 presents four cutting edges (228, 230, 232, 234)at the juncture between the peripheral flank surface 182 and theperipheral rake surface 178. When in operation, the milling insert hasan orientation such that one of the cutting edge (i.e., a selected oneof the cutting edges) engages the workpiece so as to perform achipforming and material removal operation. The vicinity where thecutting edge engages the workpiece can be considered to be the cuttinglocation.

As mentioned above, milling insert 170 further includes a diverter plate174. Diverter plate 174 has a central body 240 that presents a generallyfrusto-conical shape. Central body 240 further has a top face 242 and abottom face 244. Four tapered flanges (246, 248, 250, 252) extend in aradial outward direction from near the bottom face 244 of the diverterplate 174. Since each one of the tapered flanges (246, 248, 250, 252) isalike, a description of tapered flange 246 will suffice for adescription of the other tapered flanges. Tapered flange 246 has aninclined top surface 256 disposed at an included angle “C” with respectto the top surface 242 as shown in FIG. 11. Tapered flange 246 has aninclined bottom surface 258 disposed at an included angle “D” withrespect to the top surface 242 as shown in FIG. 11. Inclined top surface256 and inclined bottom surface 258 intersect to define a peripheraledge 260.

In this specific embodiment, the complete milling insert 170 is formedby the assembling together of the milling insert body 172 and thediverter plate 174. As mentioned above, the milling insert body 172 andthe diverter plate 174 can be affixed together by any one of a number oftechniques. In addition, it should be appreciated that the millinginsert body may be made from one material and the diverter plate madefrom another material. In other words, the milling insert body and thediverter plate can be made from different materials. By making themilling insert body and diverter plate from different materials, incertain instances an advantage can be gained over an assembly (i.e.,milling insert body and diverter plate) made from the same materials.

To assembly together these components, the central body 240 of thediverter plate 174 is positioned within the cavity in the rake surfaceof the milling insert body, and the diverter plate 174 is firmly pushedagainst the milling insert body 172 so that there is close contactbetween the two components. Such close surface-to-surface contact isshown in FIG. 14 wherein the sealing surface 214 and its proximatesurface area of the central body 240 (which is designated as region 254in FIG. 12 and 14) are in intimate contact.

When there is intimate close contact between the selected surface areasof the diverter plate 174 and the milling insert body 172, a seal isformed between each one of the sealing surfaces (214, 216, 218, 220) andthe proximate surface area of the central body portion 240 of thediverter plate 174. These seals help define each one of a plurality ofdiscrete internal channels that are essentially in fluid isolation fromone another. Each discrete internal channel is defined between thediscrete depression, the corresponding tapered flange (of the diverterplate) and the proximate surface area of the central body portion of thediverter plate.

It should be appreciated that in the case of a two-piece (i.e., themilling insert body and the diverter plate) milling insert, these sealsmay be formed via secure surface-to-surface contact in the case of astrong force (e.g., a clamping force) exerted against the milling insertto urge the diverter plate against the milling insert body. In the casewhere a single piece milling insert is formed by joining together themilling insert body and the diverter plate, the seal could be formed dueto the joinder, such as, for example, by sintering or brazing, of thecomponents together along the adjacent surface areas. The same is truein the case of where the components are joined along adjacent surfaceareas by adhesive or the like. Finally, in the case where the millinginsert is a monolithic body, the discrete internal channels (which couldhave a geometry like that of the interior channels formed via theassembly of the milling insert body and the diverter plate) would beformed by as internal channels in the interior of the part duringformation.

In this specific embodiment, there are four discrete internal channelswherein FIG. 14 shows a representative one of these internal channelsdesignated as 266. Since the internal channels present essentially thesame geometry, the following description of internal channel 266 willsuffice for a description of the other internal channels. Discreteinternal channel 266 has an inlet 268 (see FIG. 13) that opens adjacentto the bottom surface 180 (of the milling insert body 172) and thebottom face 244 of the diverter plate 174. Inlet 268 is offset in theradial outward direction from the central axis H-H of the milling insert170. As can be seen in FIG. 13, each one of the inlets of the otherinternal channels is offset from the central axis H-H.

Internal channel 266 has an outlet 270 for the exit of coolant as shownby the arrows in FIG. 14. Each one of the outlets 270 opens adjacent tothe peripheral rake surface 178 and the corresponding tapered flangethat extends from the diverter plate. Each internal channel correspondsto a cutting edge so that when the internal channel is in fluidcommunication with the coolant source, the internal channel will providefor the flow of coolant toward the corresponding cutting edge. As shownin FIG. 14, the coolant exits the internal channel in the form of afan-shaped spray (see arrows in FIG. 14).

Milling insert assembly 150 further contains a clamp 280 that containsan aperture 282 and a peripheral surface 284. The aperture 282 isdesigned to receive a threaded member to affix the clamp 280 to theclamp seating surface 84 wherein the threaded member passes through theaperture and engages the threaded hole 90 in the clamp seating surface84.

The milling insert assembly 150 is affixed in the pocket 52 of themilling cutter assembly 40 in such a fashion that the shim 152 issecured to the seating surface 62 via a threaded member that passesthrough fastener bore 160 and engages threads in the threaded bore 68.The bottom surface 156 of the shim 152 presses firmly against theseating surface 62. Shim 152 has an orientation such that the coolantbore 166 is in alignment with the opening 77 (and coolant passage 76).

Milling insert 170 is positioned within the pocket 52 so that the bottomsurface 180 thereof is securely against the top surface 154 of the shim152. The milling insert 170 has an orientation so that a selected one ofthe lobes (202, 204, 206, 208) of the central coolant passage 200 is inalignment with the coolant bore 166 in the shim 152. The milling insert170 is in fluid communication with the coolant source via the coolantpassage 76 and the central coolant reservoir 94 whereby coolant may flowinto the milling insert 170. Then, coolant flows through the millinginsert 170 via the discrete internal channel that corresponds to thelobe aligned with the coolant passage 166.

When in the orientation illustrated by FIGS. 13 through 15, coolant fromthe coolant source passes through the milling cutter body 42 in that itflows via the passages (118, 124) in the lock screw 106 into the centralcoolant reservoir 94. Coolant passes out of the coolant reservoir 94 viathe coolant passages 76 and through the coolant bore 166 through theinlet 268 into the discrete internal channel 266 that corresponds tolobe 206, which is the lobe aligned with the coolant passage 166.Coolant travels through the discrete internal channel 266, and thenexits the internal channel 266 at the outlet 270 thereof. Coolant exitsalong the length defined by a portion of the peripheral edge of thecorresponding flange 250 of the diverter plate 174 (see the arrowsadjacent to flange 250 in FIG.14). The coolant exits in such a fashionso as to comprise a direct spray on the corresponding cutting edge 232,and thus, there is provided a flow of coolant directly to the vicinityof the engagement of the cutting edge with the workpiece.

As can be appreciated, there will come a point during the millingoperation that the milling insert 170 will need to be indexed orrepositioned to present a new cutting edge for engagement with theworkpiece. In the case of the indexable milling insert, this means thatthe milling insert 170 will be rotated in the pocket 52 to present a newcutting edge. By rotating the milling insert 170 in the pocket 52, thecoolant bore 166 in the shim 152 will be in alignment with a differentdiscrete internal channel wherein this internal channel corresponds tothe new cutting edge. When in operation, coolant will be supplied in thevicinity where the new cutting edge engages the workpiece.

The fact that the coolant bore 166 of the shim 152 and the lobes of themilling insert 170 are offset from the geometric centers of the shim andthe bottom surface 180 of the milling insert 170, respectively, providesfor the feature that a different discrete internal channel (whichcorresponds to the new cutting edge) receives coolant to supply to thenew cutting edge in engagement with the workpiece.

Referring to FIGS. 16 and 17, there is shown another specific embodimentof a milling insert 290 that is illustrated as a multi-componentstructure in that there is a mediate milling insert body and a pair ofopposite rake plates that can be affixed to the mediate milling insertbody. The opposite rake plates can be attached or affixed to the mediatemilling insert body in any one of a number of different ways. In thisregard, these components can be affixed together by adhesive or braze orthe like. The milling insert body and the diverter plate may be sinteredtogether to form a single milling insert. As still another alternative,the structure defined by the combination of the milling insert body andrakes plates can be formed as a monolithic body via a powdermetallurgical technique that is suitable to make a body with an internalchannel. The above-referred patent documents that are exemplary ofpowder metallurgical methods to make a body with internal passages areapplicable to this milling insert.

It should be appreciated that the mediate milling insert body may bemade from one material and one or both of the rake plates made fromanother material. In other words, the milling insert body and either oneor both rake plates can be made from different materials including eachrake plate made from a different material. By making the milling insertbody and the rake plates (one or both) from different materials, incertain instances an advantage can be gained over an assembly (i.e.,milling insert body and one or both rake plates) made from the samematerials.

Milling insert 290 defines eight cutting edges that comprise fourcutting edges adjacent to one rake surface of the milling insert andfour cutting edges adjacent to the other rake surface of the millinginsert 290. Milling insert 290 also contains discrete internal channelswherein each internal channel is essentially in fluid isolation from theother internal channel. These internal channels comprise a first set offour discrete internal channels wherein each one of these channels ofthe first set corresponds with one of the cutting edges adjacent to theone rake surface. These internal channels comprise a second set of fourdiscrete internal channels wherein each one of these channels of thesecond set corresponds with one of the cutting edges adjacent to theother rake surface.

Milling insert 290 includes a mediate milling insert body 292. Themilling insert body 292 has a peripheral flank surface 294, as well asopposite faces 296 and 298. The mediate milling insert body 292 furtherpresents a peripheral portion of the rake surface 300 on one face 296and another peripheral portion of the rake surface 302 on the other face298. The intersection between the peripheral flank surface 294 and theperipheral portion of the rake surface 300 define cutting edges 304,306, 308 and 310 wherein these cutting edges are adjacent to one rakesurface of the milling insert. The intersection between the peripheralflank surface 294 and the peripheral portion of the rake surface 302define cutting edges 312, 314, 316 and 318 wherein these cutting edgesare adjacent to another rake surface of the milling insert.

Milling insert body 292 further contains a central aperture 320 thatpasses completely through the milling insert body. Milling insert boy292 further contains a plurality of peripheral apertures that passcompletely through the milling insert body 292 and are located adjacentto the periphery of the milling insert body 292 wherein these aperturescan be considered to comprise a first set of apertures and a second setof apertures. Referring to FIG. 17, the first set of apertures comprisesapertures 322, 324, 326 and 328, and the second set of aperturescomprises apertures 332, 334, 336 and 338.

Milling insert 290 further includes one rake plate 342 that has anexterior surface 344 and an interior surface 346. One rake plate 342contains a central aperture 348, as well as a plurality of passages(350, 352, 354, 356) located adjacent to the periphery of the one rakeplate. Each one of these passages (350, 352, 354, 356) passes completelythrough the one rake plate 342. One rake plate 342 further contains aplurality of troughs (360, 362, 364, 366) (see FIG. 16A) wherein eachone of the troughs is adjacent to one of the apertures.

Milling insert 290 further includes another rake plate 370 that has anexterior surface 372 and an interior surface 374. The other rake plate370 contains a central aperture 376, as well as a plurality of passages(378, 380, 382, 384) located adjacent to the periphery of the one rakeplate. Each one of these passages (378, 380, 382, 384) passes completelythrough the other rake plate 370. Other rake plate 370 further containsa plurality of troughs (388, 390, 392, 394) wherein each one of thetroughs is adjacent to one of the apertures.

When the rake plates (342 and 370) are assembled to the mediate millinginsert body 292, there are formed a first set of discrete internalchannels wherein a representative channel of the first set of discretechannels is designated 400 in FIG. 17. The more detailed description ofchannel 400 will suffice for such a description of the other channels ofthe first set since they are essentially the same.

In reference to FIG. 17, internal channel 400 comprises peripheralaperture 328, passage 384 contained in the other rake plate 370 and thetrough 366 contained in the one rake plate 342. The exterior opening forpassage 384 functions as an inlet for the internal channel 400 throughwhich coolant enters from the coolant source when the internal channel400 is in fluid communication with the coolant source. When in thiscondition, coolant flows through passage 384 and peripheral aperture 328and into trough 366 where it is directed over the notches 286 and awayfrom the milling insert toward the vicinity of the cutting edge 310. Itcan thus be seen that internal channel 400 provides a pathway forcoolant to flow so as to provide a direct spray of coolant in thevicinity of the corresponding cutting edge.

As can be appreciated, each one of the internal channels in the firstset of discrete internal channels has an inlet in the other rake plate370 and an outlet in the one rake plate 342. Each one of the channels ofthe first set of discrete internal channels has a corresponding one ofthe cutting edges (304, 306, 308, 310) adjacent to the one face 296.Referring to FIGS. 16 and 16A, the four interior channels of the firstset of interior channels are described below.

The first one of the interior channels comprises passage 378 in theother rake plate 370, the peripheral aperture 322 in the mediate millinginsert body and the trough 360 in the one rake plate 342. The firstinterior channel correspond to cutting edge 304. The second one of theinterior channels comprises passage 380 in the other rake plate 370, theperipheral aperture 324 in the mediate milling insert body and thetrough 362 in the one rake plate 342. The second interior channelcorresponds to cutting edge 306. The third one of the interior channelscomprises passage 382 in the other rake plate 370, the peripheralaperture 326 in the mediate milling insert body and the trough 364 inthe one rake plate 342. The third one of the interior channelscorresponds to cutting edge 308. The fourth one of the interior channels(which is illustrated as channel 400 in FIG. 17) comprises passage 384in the other rake plate 370, the peripheral aperture 328 in the mediatemilling insert body and the trough 366 in the one rake plate 342. Thefourth interior channel correspond to cutting edge 310.

When the rake plates (342 and 370) are assembled to the mediate millinginsert body 292, there is also formed a second set of discrete internalchannels wherein a representative channel of the second set of discretechannels is designated 402 in FIG. 17. The more detailed description ofchannel 402 will suffice for such a description of the other channels ofthe second set since they are essentially the same.

In reference to FIG. 17, internal channel 402 comprises peripheralaperture 334, passage 352 contained in the one rake plate 342 and thetrough 390 contained in the other rake plate 370. The exterior openingfor passage 352 functions as an inlet for the internal channel 402through which coolant enters from the coolant source when the internalchannel 402 is in fluid communication with the coolant source. When inthis condition, coolant flows through passage 352 and peripheralaperture 328 and into trough 390 where it is directed over the notches286 and away from the milling insert toward the vicinity of the cuttingedge 314. It can thus be seen that internal channel 402 provides apathway for coolant to flow so as to provide a direct spray of coolantin the vicinity of the corresponding cutting edge.

As can be appreciated, each one of the internal channels in the secondset of discrete internal channels has an inlet in the one rake plate 342and an outlet in the other rake plate 370. Each one of the channels ofthe second set of discrete internal channels has a corresponding one ofthe cutting edges (312, 314, 316, 318) adjacent to the other face 298.Referring to FIGS. 16 and 16A, the four interior channels of the secondset of interior channels are described below.

The first one of the interior channels (of the second set of channels)comprises passage 350 in the one rake plate 342, the peripheral aperture332 in the mediate milling insert body and the trough 388 in the otherrake plate 370. The first interior channel corresponds to cutting edge312. The second one of the interior channels (which is illustrated asinternal channel 402 in FIG. 12) comprises passage 352 in the one rakeplate 342, the peripheral aperture 334 in the mediate milling insertbody and the trough 390 in the other rake plate 370. The second interiorchannel corresponds to cutting edge 314. The third one of the interiorchannels comprises passage 354 in the one rake plate 342, the peripheralaperture 336 in the mediate milling insert body and the trough 392 inthe other rake plate 370. The third one of the interior channelscorresponds to cutting edge 316. The fourth one of the interior channelscomprises passage 356 in the one rake plate 342, the peripheral aperture338 in the mediate milling insert body and the trough 394 in the otherrake plate 370. The fourth interior channel corresponds to cutting edge318.

The above description shows that coolant is supplied to any one of thecutting edges that is selected to be in engagement with the workpiece.In this regard, when affixed to the pocket of a milling cutter body suchas generally shown in FIG. 1, a threaded member passes through thecentral aperture 320, as well as a central passage in an optional shim(not illustrated), so as to engage a threaded bore in the seatingsurface of a pocket that carries a milling insert assembly that usesmilling insert 290. The seating surface of the pocket that is generallyparallel to the rake plates contains an opening to a coolant passagethat is, in turn, in communication with the coolant source through thecentral coolant reservoir. The position on the seating surface of theopening to the coolant passage is such that the inlet to the internalchannel corresponding to the selected (or engaged) cutting edge is inalignment with the opening to the coolant passage.

In operation, coolant is supplied through the internal channel to theselectively engaged cutting edge. When it is necessary to present a newcutting edge, the milling insert is indexed to another position topresent the new cutting edge. When in the new position, the internalchannel that corresponds to the new cutting edge is now in alignment,and hence, fluid communication with the opening of the coolant passage.Thus, coolant is supplied to the new cutting edge that is engagementwith the workpiece.

Referring to FIGS. 19 through 22, there is shown still another specificembodiment of a milling insert generally designated as 410. Millinginsert 410 has a milling insert body 412 that presents a peripheralflank surface 414 and a peripheral rake surface 416. Milling insert body412 defines cutting edges (418, 420, 422, 424) at the intersectionbetween the peripheral flank surface 414 and the peripheral rake surface416. Milling insert body 412 has a bottom surface 426.

Milling insert body 412 contains a central aperture 428 that passescompletely through the body. Milling insert body 412 contains a centralcavity 430 that further contains troughs (432, 434, 436, 438). Millinginsert body 412 contains a coolant passage (440, 442, 444, 446) adjacentto each one of the troughs (423, 434, 436, 438). A description ofcoolant passage 442 is sufficient for a description of the other coolantpassages wherein coolant passage 442 has an inlet 448 and an outlet 450.Coolant enters the passage through the inlet and exits the passagethrough the outlet.

Milling insert 410 further includes a milling rake plate 470. Millingrake plate 470 has an exterior surface 472 and an interior surface 474,as well as contains a central aperture 476 therethrough.

Milling insert 410 affixes to the pocket of the milling cutter body in afashion generally like that for milling insert 290 in that a threadedmember passes through the central aperture to engage a threaded bore inthe seating surface of a pocket that carries a milling insert assemblythat uses the milling insert. More specifically, FIGS. 23 and 24 show amilling cutter assembly generally designated as 480. Milling cutterassembly 480 includes a milling cutter body 482 that has an axialforward end 484 and an axial rearward end 486. There is a head portion488 at the axial forward end 484 ad a shank 490 depends from the headportion 488. The head portion 488 contains a pocket 494 that has abottom seating surface 496 and a pair of upstanding side seatingsurfaces 498 and 500. The head portion 488 contains a threaded hole (oraperture) 502 that opens in the bottom seating surface 496 of the pocket494. The milling cutter body 482 contains a coolant passage 504 thatopens at the bottom seating surface 496 of the pocket 494.

In reference to the attachment of the milling insert 410 to the millingcutter body 482, the milling insert 410 is positioned in the pocket 494so that the central apertures (428 and 476) of the milling insert body412 and rake plate 470, respectively, are in alignment with the threadedhole 502. The screw 506 is passed through the central apertures (428 and476) and into engagement with the threaded hole 502 whereby the screw505 is tightened down to secure the milling insert 410 to the millingcutter body 482.

It should be appreciated that the milling insert 410 is oriented in thepocket 494 so that a selected one of the cutting edges is positioned tobe in engagement with the workpiece. In this regard and as shown inFIGS. 23-24, the milling insert 410 is oriented so that cutting edge 420is in position to engage the workpiece and the corresponding coolantpassage 442 is in alignment with the coolant passage 504 opening in thebottom seating surface 496. When in this position, coolant passes intothe milling insert 410 via coolant passage 442 and flows through themilling insert 410 so as to exit in a spray adjacent to the cutting edge420.

In operation, the coolant passage that corresponds to the cutting edge(420) selected to be in engagement with the workpiece is in alignmentwith the opening to the coolant passage in the seating surface. Coolantis supplied to the engaged cutting edge through the coolant passage 442in the milling insert. When it is necessary to present a new cuttingedge, the milling insert is indexed to another position to present thenew cutting edge. When in the new position, the internal channel thatcorresponds to the new cutting edge is now in alignment, and hence,fluid communication with the opening of the coolant passage. Thus,coolant is supplied to the new cutting edge.

Referring to the structure in FIGS. 25-26, there is shown anotherspecific embodiment of a milling cutter body generally designated as510. Milling cutter body 510 contains a plurality of pockets 514 at theperiphery thereof. Each one of the pockets 514 has a side seatingsurface 516 and a bottom seating surface 518. Each pocket 514 also has aleading surface 520. A clamp 522 is secured to the milling cutter body510 at a point rotationally ahead of the pocket 514, but close enough tothe pocket 514 to be able to bias against the surface of a millinginsert retained within the pocket 514. The side seating surface 516contains a cut out portion 526 that surrounds the coolant passage 532that opens at the side seating surface 516.

In reference to the attachment of the milling insert 170 in the pocket514, the bottom surface 180 of the milling insert 170 is placed againstthe side seating surface 516 so that one of the lobes (202, 204, 206,208) is in alignment with (or opens into) the volume defined by the cutout 526. The clamp 522 is positioned so that it acts against the millinginsert 170 whereby upon being tightened, the clamp securely maintainsthe milling insert 170 in the pocket 514. Coolant passes into themilling insert 170 through the coolant passage 532 and the volumedefined by cut out 526. Coolant then passes through the milling insert170 as described hereinabove, and exits in a spray adjacent to theselected cutting edge that is in engagement with the workpiece.

The milling cutter assembly has a number of advantages because itprovides coolant to the underneath side of the cutting edge at theinterface of the cutting edge and the workpiece. As a result, thecoolant provides for a reduction of the negative impact of the heatbuild-up at the milling insert-workpiece interface. As a further result,the presence of the coolant provides for an improvement in thelubrication at the milling insert-chip interface to avoid or reduceaccumulation of workpiece material on the milling insert. In addition,the coolant stream facilitates the evacuation of the chips from thevicinity of the milling insert-chip interface to avoid re-cutting thechip.

For the specific embodiments shown herein, it can be seen that thecoolant exits at a location on the underneath side of the cutting edgeat the interface of the cutting edge and the workpiece. As a result, thecoolant provides for a reduction of the negative impact of the heatbuild-up at the milling insert-workpiece interface. As a further result,the presence of the coolant provides for an improvement in thelubrication at the milling insert-chip interface to avoid or reduceaccumulation of workpiece material on the milling insert. In addition,the coolant stream facilitates the evacuation of the chips from thevicinity of the milling insert-chip interface to avoid re-cutting thechip.

It is apparent that the present invention provides a milling cutter, aswell as a milling insert, used for chipforming and material removaloperations wherein there is an improved delivery of coolant to theinterface between the milling insert and the workpiece. A number ofadvantages exist as a result of the improvement in the coolant delivery.

In this regard, the present invention provides a milling cutter, as wellas a milling insert, used for chipforming and material removaloperations wherein there is an improved delivery of coolant to theinterface between the milling insert and the workpiece (i.e., thelocation on the workpiece where the chip is generated). As a result, thecoolant provides for a reduction of the negative impact of the heatbuild-up at the milling insert-workpiece interface. As a further result,the presence of the coolant provides for an improvement in thelubrication at the milling insert-chip interface to avoid or reduceaccumulation of workpiece material on the milling insert. In addition,the coolant stream facilitates the evacuation of the chips from thevicinity of the milling insert-chip interface to avoid re-cutting thechip.

The patents and other documents identified herein are herebyincorporated by reference herein. Other embodiments of the inventionwill be apparent to those skilled in the art from a consideration of thespecification or a practice of the invention disclosed herein. It isintended that the specification and examples are illustrative only andare not intended to be limiting on the scope of the invention. The truescope and spirit of the invention is indicated by the following claims.

1. A cutting insert for use in chipforming and material removal from aworkpiece wherein coolant is supplied to the cutting insert from acoolant source, the cutting insert comprising: at least one discretecutting location; at least one distinct internal channel thatcorresponds to the cutting location; and the internal channel has aninlet to receive coolant and an outlet to exit coolant, the outlet beingproximate to the cutting location, and the inlet being radial inward ofthe outlet.
 2. The cutting insert according to claim 1 wherein thecutting insert having at least two of the distinct cutting locations andat least two of the discrete internal channels, each one of the internalchannels corresponds to one of the cutting locations, and each one ofthe internal channels having the inlet and the outlet wherein the inletis radial inward of the outlet.
 3. The cutting insert according to claim1 further having a rake surface, a bottom surface and a peripheral flanksurface, and the inlet of each one of the internal channels opening inthe bottom surface and the outlet of each one of the internal channelsopening in the rake face.
 4. The cutting insert according to claim 3wherein each one of the cutting locations comprises a discrete cuttingedge formed at the intersection of the rake surface and the peripheralflank surface.
 5. The cutting insert according to claim 1 wherein aselected one of the cutting locations being in engagement with theworkpiece, and the internal channel corresponding to the selectedcutting location being in communication with the coolant source.
 6. Thecutting insert according to claim 5 wherein the internal channelscorresponding to the cutting locations not in engagement with theworkpiece being in substantial fluid isolation from the coolant source.7. The cutting insert according to claim 5 wherein the outlet of theinternal channel corresponding to the selected cutting location beingoriented to provide a direct spray of coolant adjacent to the selectedcutting location.
 8. The cutting insert according to claim 5 wherein theselected cutting location being the sole cutting location to receive adirect spray of the coolant.
 9. The cutting insert according to claim 1having a central axis passing between the rake surface and the bottomsurface, and each one of the inlets being disposed offset from thecentral axis.
 10. The cutting insert according to claim 1 wherein atleast a portion of the cutting insert being made from one of thematerials selected from the group consisting of tools steels, cementedcarbides, cermets, and ceramics by a powder metallurgical technique. 11.The cutting insert according to claim 1 wherein at least a portion ofthe cutting insert having at least one coating layer thereon.
 12. Thecutting insert according to claim 1 comprising a cutting insert bodydefining a peripheral flank surface, a bottom surface and a part of arake surface of the cutting insert, and a plate attached to the cuttinginsert body and defining at least another part of the rake surface. 13.The cutting insert according to claim 1 wherein each one of the internalchannels having a volume, and the volume of each internal channeldecreasing in a radial outward direction.
 14. The cutting insertaccording to claim 1 wherein the cutting insert comprising a mediatecutting insert body having a peripheral flank surface and a peripheralportion of opposite rake surfaces wherein each one of the cuttinglocations comprises a discrete cutting edge formed at intersectionsbetween the peripheral flank surface and the peripheral portions of therake surfaces, and a pair of rake plates attached to the mediate cuttinginsert body wherein each one of the rake plates defining in part itscorresponding one of the rake surface.
 15. The cutting insert accordingto claim 14 wherein the mediate cutting insert body is made of amaterial different from the material from which either one of the rakeplates is made.
 16. The cutting insert according to claim 1 comprising aperipheral rake surface and a pair of opposite rake surfaces, andwherein each one of the cutting locations comprising a discrete cuttingedge at the intersections between the rake surfaces and the peripheralflank surface.
 17. The cutting insert according to claim 1 furtherincluding an aperture adapted to permit a fastener to pass so as toaffix the cutting insert to a cutter body.
 18. The cutting insertaccording to claim 1 further including a surface that is contacted by aclamp so as to affix the cutting insert to a cutter body.
 19. A cuttinginsert for use in chipforming and material removal from a workpiecewherein coolant is supplied to the cutting insert from a coolant source,the cutting insert comprising: a cutting insert body presenting aplurality of discrete cutting locations; the cutting insert bodycontaining a plurality of discrete depressions corresponding to one ofthe cutting locations and extending toward its corresponding one of thecutting locations; a plate having a central body with a top face and abottom face, and a plurality of tapered flanges; and the plate beingaffixed to the cutting insert body wherein each one of the taperedflanges being received within a corresponding one of the discretedepressions so that each one of the discrete depressions and itscorresponding one of the tapered flanges and a portion of the centralbody define one of a plurality of discrete internal channels whereineach one of the discrete internal channels corresponds to one of thecutting locations, and each one of the internal channels has an outletto exit coolant being proximate to the corresponding cutting locationand an inlet to receive coolant being radial inward of the outlet. 20.The cutting insert according to claim 19 wherein the cutting insert bodycontaining a central coolant passage, and the discrete depressionsintersecting the central coolant passage, and the central coolantpassage receiving the plate so as to define the inlets for each one ofthe internal channels.
 21. The cutting insert according to claim 19wherein each one of the discrete depressions has a radial inner portionand a radial outer portion, and the radial inner portion intersectingthe central coolant passageway and the radial outer portion beingadjacent to the corresponding one of the cutting locations.
 22. Thecutting insert according to claim 19 wherein each one of the internalchannels having a volume, and the volume of each one of the internalchannels decreasing in a radial outward direction.
 23. The cuttinginsert according to claim 19 wherein one or both of the cutting insertbody and the plate is made from one of the materials selected from thegroup consisting of tool steels, cemented carbides, cermets, andceramics by a powder metallurgical technique.
 24. The cutting insertaccording to claim 19 wherein the central body of the plate being of agenerally frusto-conical shape.
 25. The cutting insert according toclaim 19 wherein the tapered flanges being adjacent to the top face ofthe plate and extending in a generally radial outward direction.
 26. Thecutting insert according to claim 19 wherein the cutting insert bodycontains a first aperture and the plate contains a second aperture; andwhen the plate is affixed to the cutting insert body, the first apertureand the second aperture being in alignment so as to permit a fastener topass therethrough so as to affix the cutting insert to a cutter body.27. The cutting insert according to claim 19 wherein the cutting insertbody including a surface that is contacted by a clamp so as to affix thecutting insert to a cutter body.
 28. A cutting insert for use inchipforming and material removal from a workpiece wherein coolant issupplied to the cutting insert from a coolant source, the cutting insertcomprising: a cutting insert body presenting at least one discretecutting location; the cutting insert body containing at least onediscrete depression that corresponds to the cutting location and extendstoward the corresponding cutting location; a plate having a central bodywith a top face and a bottom face, and at least one tapered flange; andthe plate being affixed to the cutting insert body wherein the taperedflange being received within the discrete depression so that thediscrete depression and the corresponding tapered flange and a portionof the central body define at least one discrete internal channel thatcorresponds to the cutting location, and the internal channel has anoutlet to exit coolant being proximate to the corresponding cuttinglocation and an inlet to receive coolant being radial inward of theoutlet.
 29. A cutting insert for use in chipforming and material removalfrom a workpiece wherein coolant is supplied to the cutting insert froma coolant source, the cutting insert comprising: a mediate cuttinginsert body defining a peripheral flank surface and a peripheral portionof opposite rake surfaces wherein the peripheral flank surfaceintersects the peripheral portion of the opposite rake surfaces to formdiscrete cutting locations; a pair of rake plates attached to themediate cutting insert body, and each one of the rake plates defining inpart its corresponding one of the rake surfaces; the mediate cuttinginsert body and the rake plates together defining a first group of aplurality of discrete internal channels and a second group of aplurality of discrete internal channels; each one of the first group ofdiscrete internal channels corresponding to one of the cutting locationsat the intersection of one of the rake surfaces and the peripheral flanksurface, and each one of the second group of discrete internal channelscorresponding to one of the cutting locations at the intersection ofother of the rake surfaces and the peripheral flank surface; and eachone of the first group of the discrete internal channels having an inletopening at the other of the rake surface and an outlet opening at theone rake surface adjacent to its corresponding cutting location, andeach one of the second group of the discrete internal channels having aninlet opening at the one of the rake surface and an outlet opening atthe other rake surface adjacent to its corresponding cutting location.30. The cutting insert according to claim 29 wherein a selected one ofthe cutting locations being in engagement with the workpiece, and theinternal channel corresponding to the selected cutting location being incommunication with the coolant source.
 31. The cutting insert accordingto claim 29 wherein the internal channels corresponding to the cuttinglocations not in engagement with the workpiece being in substantialfluid isolation from the coolant source.
 32. The cutting insertaccording to claim 29 wherein the outlet of the internal channelcorresponding to the selected cutting location being oriented to providea direct spray of coolant adjacent to the selected cutting location. 33.The cutting insert according to claim 29 wherein the selected cuttinglocation being the sole cutting location to receive a direct spray ofthe coolant.
 34. The cutting insert according to claim 29 having acentral axis passing between the rake surface and the bottom surface,and each one of the inlets being disposed offset from the central axis.35. The cutting insert according to claim 29 wherein the mediate cuttingbody being made from a material different from that of the rake plates.36. A milling cutter for use in chipforming and material removal from aworkpiece wherein coolant is supplied to the milling cutter from acoolant source, the milling cutter comprising: a milling cutter bodycontaining a coolant reservoir, the milling cutter body furthercontaining a pocket having a pocket opening in communication with thecoolant source, and the milling cutter body containing a fluidpassageway that provides fluid communication between the coolantreservoir and the pocket; and a cutting insert comprising at least onediscrete cutting location; at least one distinct internal channel thatcorresponds to the cutting location; and the internal channel has aninlet to receive coolant and an outlet to exit coolant, the outlet beingproximate to the cutting location, and the inlet being radial inward ofthe outlet.
 37. The milling cutter according to claim 36 wherein thecutting insert having at least two of the distinct cutting locations andat least two of the discrete internal channels, each one of the internalchannels corresponds to one of the cutting locations, and each one ofthe internal channels having the inlet and the outlet wherein the inletis radial inward of the outlet.
 38. The milling cutter according toclaim 36 wherein the cutting insert containing an aperture, and afastener passing through the aperture whereby the fastener affixed thecutting insert to the milling cutter body.
 39. The milling cutteraccording to claim 38 further including a clamp attached to the millingcutter body, and the clamp contacting a portion of the cutting insert soas to affix the cutting insert to the milling cutter body.